At present, different types of membranes made up of synthetic or biopolymer based materials are available which are primarily used in numerous applications such as separation of different types of mixtures including oil-water emulsion using high pressure.
Oily water emulsions are one of the main pollutants released into water by industries including Asia's largest ship breaking yard in Alang, Gujarat, India and domestic sewage. Oily water in inland waterways and coastal zone is also one of the most serious issues of water pollution which needs to be resolved urgently.
Reference may be made to “Effect of Polyvinylpyrrolidone Molecular Weights on Morphology, Oil/Water Separation, Mechanical and Thermal Properties of Polyetherimide/Polyvinylpyrrolidone Hollow Fiber Membranes” by Xu, Chung, & Huang (Journal of Applied Polymer Science, 74, 2220-2233, 1999) wherein a process for making polyetherimide (PEI) hollow fiber membranes using polyvinylpyrrolidones (PVP) as additives for oil/water separation has been reported.
Reference may be made to “Polymeric asymmetric membranes made from polyetherimide/polybenzimidazole/poly (ethylene glycol) (PEI/PBI/PEG) for Oil-surfactant-water separation” by Xu, Chung, Loh, & Lim (Journal of Membrane Science, 158 (1999) 41-53) wherein a process for making the asymmetric hollow fiber membranes using polyetherimide (PEI) as the membrane material and polybenzimidazole (PBI) and poly(ethylene glycol) (PEG 600) as the additives, for oil-surfactant-water separation.
Reference may be made to “Surface modification of ultrafiltration membranes by preadsorption of a negatively charged polymer I. Permeation of water soluble polymers and inorganic salt solutions and fouling resistance properties” by Reddy, Mohan, Bhattacharya, Shah, Ghosh (Journal of Membrane Science 214 (2003) 211-221) wherein a process for surface modification of Polyethersulfone ultrafiltration membranes (MWCO: 9000, 35,000 and 85,000) has been reported by preadsorption of poly(sodium 4-styrenesulfonate) (PSS) upon the permeation of aqueous solution of the polymer for about 100 min. Membranes with lower MWCO values were modified primarily on the top surface, whereas high MWCO membranes were modified both on the surface and pore walls as well.
Reference may be made to “Separation of water from hydrocarbons and halogenated hydrocarbons” by Taylor and Mich (U.S. Pat. No. 4,857,081, 1989) wherein a process for making an apparatus for separating water from a water and hydrocarbon mixture and water from a water and halogenated hydrocarbons includes membrane consisting essentially of nonporous self supported hallow fibres of cuproammonium cellulose.
Chen, Su, Zheng, Wang, Jiang (Journal of Membrane Science 337 (2009) 98-105) has reported the improved oil/water separation performance of cellulose acetate-graft-polyacrylonitrile membranes.
Panpanit, Visvanathan and Muttamara (Water Science & Technology, 41 (2000), 109-116) has reported the separation of oil-water emulsion from car washes by UF and NF membrane.
Reference may be made to “Demulsification of water-in-oil emulsion by using porous glass membrane” by Sun, Duan, Li, and Zhou (Journal of Membrane Science 146 (1998) 65-72) wherein a process for demulsification of water-in-oil emulsion by using porous glass membrane has been reported.
Yang, Zhang, Xu, Shi (Journal of Membrane Science 142 (1998) 235-243) has reported the preparation and application of ZrO2/a-Al2O3 MF membrane in oil-water separation.
Reference may be made to “The separation of oil from an oil-water-bacteria mixture using a hydrophobic tubular membrane” by Konishi, et al. (Biochemical Engineering Journal 24 (2005) 49-54) wherein a hydrophobic polytetrafluroethylene (PTFE) tubular membrane was effective in separating n-tetradecane, a model oil from 50% (v/v) n-tetradecane in water.
Ahmad, Ismail, and Bhatia (Desalination, 157 (2003) 87-95) have reported water recycling from palm oil mill effluent (POME) using membrane technology. Malaysia is the largest producer and exporter of palm oil. Palm oil processing is carried out in palm oil mills where oil is extracted from a palm oil fruit bunch. Large quantities of water are used during the extraction of crude palm oil from fresh fruit bunch, and about 50% of the water results in palm oil mill effluent (POME). The disposal of this highly polluting effluent is becoming a major problem if it is not treated properly according to the stringent standard limit imposed by The Malaysian Department of Environment for effluent discharged. A POME treatment system based on membrane technology shows high potential for eliminating the environmental problem, and in addition, this alternative treatment system offers water recycling. The treated effluent has high quality and crystal clear water that can be used as the boiler feed water or as a source of drinking water production.
Reference may be made to “Agar-based films for application as polymer electrolytes” by Raphael, et al. (Electrochimica Acta 55 (2010) 1455-1459) wherein a new types of polymer electrolytes based on agar have been prepared and characterized by impedance spectroscopy, X-ray diffraction measurements, UV-Vis spectroscopy and scanning electronic microscopy (SEM). The best ionic conductivity has been obtained for samples containing a concentration of 50 wt % of acetic acid.
Reference may be made to “Semipermeable polymers and method for producing same” by Buschmann (U.S. Pat. No. 8,147,735) wherein the patent disclosed preparation of high performance polymer membranes from aromatic polyimide membranes via thermal treating in inert atmosphere followed by crosslinking using a UV radiation source. The membranes showed significantly improved selectivity and permeability for gas separations compared to the aromatic polyimide membranes without any treatment.
Reference may be made to “Composite polyamide reverse osmosis membrane and method of producing the same” Koo, et al. (U.S. Pat. No. 7,479,300) wherein the patent disclosed preparation of a composite polyamide reverse osmosis membrane by coating a porous polysulfone support with an aqueous solution containing 2 wt % m-phenylenediamine (MPD), and 0.1 wt % di(ethylene glycol) hexyl methyl ether. The excess solution is removed, and the coated support is dipped in 0.1 wt % organic solvent solution of trimesoyl chloride (TMC) in a mixture of alkanes having from 8 to 12 carbon atoms. After draining the TMC solution off, the resulting composite membrane is air dried and then rinsed in a basic aqueous solution. The resultant membrane exhibits a flux of 21.3 gfd and a salt rejection of 98.9% when used at 225 psi for an aqueous solution containing 2000 ppm of NaCl.
Reference may be made to “Use of a composite polymer-coated sorbent for separation, purification, desalting and concentration of biopolymers” Leiser, et al. (U.S. Pat. No. 7,018,538) wherein the a composite sorbent having an at least partial coating on a support, the coating comprising essentially polyanilines or derivatives of polyanilines, said composite is used for separation, isolation, identification, purification and/or detection of biomolecules, in particular nucleic acids, proteins, polysaccharides in an analytical or preparative scale.
Reference may be made to “High performance composite membrane” Rice, et al. (U.S. Pat. No. 6,536,605) wherein said patent discloses preparation of high quality reverse osmosis, nanofiltration, and ultrafiltration membranes by employing tandem coating techniques to coat a microporous substrate with a thin membrane on the order of 25 Å to 1.0 microns. For making reverse osmosis and nanofiltration membranes, a wet-on-wet coating process was used to coat a porous substrate with an aqueous solution followed with an organic solution to produce a cross-linked and interfacially polymerized composite membrane. A single slot coating applicators was used for the preparation of ultrafiltration membranes.
Reference may be made to “Polyion complex separation membrane with a double structure” Lee, et al. (U.S. Pat. No. 6,325,218) wherein said patent discloses a polyion complex separation membrane with a double structure, which is suitable in separation of a water-soluble mixture having ionic molecules by means of reverse osmotic pressure for the purposes of recovering expensive ionic organic materials.
Membrane having anionic polymers, as substrate, is immersed into a cationic polymer solution containing a multivalent ion cross-linking agent, thereby forming an ion complex between ionic polymers of opposite ion at the surface of the separation membrane to yield a stable separation membrane of a double structure.
Reference may be made to “Polymer and porous structure” Colquhoun, et al. (U.S. Pat. No. 5,847,075) wherein said patent disclosed a polymer characterised by presence of ylid linkages in main polymer chain. They used synthetic polymers and hazardous chemical reaction to produce desired materials and said polymers may be used to fabricate membranes for various separation processes, e.g. ultrafiltration, nanofiltration, and reverse osmosis.
Reference may be made to “Polymer porous structure and process” Colquhoun, et al. (U.S. Pat. No. 5,698,105) wherein said patent disclosed a reverse osmosis membrane having a support which itself has properties of salt rejection laminated to a layer of a cross-linked polyol. The support is a sulphonated aromatic polyether sulphone, and the polyol may be polyvinyl alcohol.
Reference may be made to “Process for forming membrane having a hydrophobic fluoropolymer surface” Moya, et al. (U.S. Pat. No. 5,554,414) wherein said patent reported a composite porous object produced from a porous polymeric substrate having its entire surface modified with a cross-linked polymer. They prepared the cross-linked polymer in-situ using an ethylenically unsaturated monomer as a cross-linker.
Reference may be made to “Composition membrane for separating water from fluids containing organic components by means of pervaporation” Neel, et al. (U.S. Pat. No. 5,334,314) wherein said patent discloses preparation of composite membrane for separating water from fluid mixtures containing organic components by means of pervaporation. Composite membrane comprised a separating layer of cross-linked polyvinyl alcohol, which was subjected to a post-cross-linking by treatment with acids. The acids are preferably hydrohalic acids, sulfurous acid, sulfuric acid, nitrous acid, nitric acid or acetic acid.
Reference may be made to “Hydrophobic polymeric membrane composites” Scarmoutzos, et al. (U.S. Pat. No. 5,286,382) wherein said patent disclosed preparation of composite porous membrane from a porous polymeric substrate having its entire surface modified with a cross-linked polymer which results in a hydrophobic and oleophobic surface. The cross-linked polymer is formed in situ from a reactant system comprising an ethylenically unsaturated monomer as a cross-linker, and, used a polymerization initiator.
Reference may be made to “Hydrophobic membrane having hydrophilic and charged surface and process” Wang, D. (U.S. Pat. No. 5,137,633) wherein the surface of a hydrophobic porous substrate is modified with an interpolymeric network of a hydrophilic crosslinked polymer and a crosslinked-polyamine epichlorohydrin resin having fixed positive charges. The hydrophobic substrate is contacted with a reaction system comprising a solution of (a) monomer precursor to the hydrophilic polymer, a nonionic or cationic polymerization initiator and a crosslinking agent and (b) a precursor to the crosslinked positively charged resin. The monomer is polymerized and cross-linked by free radical polymerization followed by heating the contacted substrate to form the charged resin.
Reference may be made to “Transparent porous membrane having hydrophilic surface and process” Pitt, et al. (U.S. Pat. No. 4,917,793) wherein the preparation of a composite, microscopically transparent, porous membrane is formed from a porous polytetrafluoroethylene membrane having desired bulk properties on which a cross-linked polymer having desired surface properties is directly coated. The composite membrane retains the porosity of the porous polymeric membrane.
Reference may be made to “Multi-layer membrane and the use thereof for the separation of liquid mixtures according to the pervaporation process” Bruschke (U.S. Pat. No. 4,915,834) wherein the patent discloses the preparation of a multi-layer membrane having a porous backing layer of polyacrylonitrile, polysulfone or the like, and an active separating layer of polyvinyl alcohol or cellulose acetate. The membrane is particularly suitable for separation of water-alcohol mixtures according to the pervaporation process.
Reference may be made to “Polymer composite membrane” Karakane, et al. (U.S. Pat. No. 4,871,461) wherein the patent discloses preparation of a permeable membrane through which water or its vapor permeates selectively which contains a polyion complex formed by the association by an ionic bond between an anionic polymer and a cationic polymer on the surface of the membrane and/or in the membrane. This membrane is useful in separation of water from an aqueous solution of an organic substance or a gaseous mixture of water with an organic substance, and exhibits excellent resistance to solvent, particularly water, and a high permeation rate and a high separation coefficient.
Reference may be made to “Composite membrane for the separation of water and method for manufacturing same” Hubner, et al. (U.S. Pat. No. 8,256,626, 2012) wherein the patent discloses preparation of a composite membrane for the separation of water with at least one separation layer of cross-linked polyvinyl alcohol, with the separation layer being subjected in a separate process step to a post-crosslinking operation with an acid or an acid-releasing compound and at least one dialdehyde.
It is evident from the background that there is no document disclosing crosslinked composite prepared from seaweed polysaccharides and amino containing biopolymers which have been utilised for preparation of a hydrophobic biocompatible crosslinked porous materials which can be used for the separation of the varieties of mixtures including oil-water mixtures under gravity-gradient.